Process and bath for pickling metals



Patented Dec. 29, 1931 UNITED STATES PATENT OFFICE VANDERVEER VOORHEES, F WHITING, INDIANA, ASSIGNOR TO STANDARD OIL COM- PANY, 0F WHITING, INDIANA, A CORPORATION OF INDIANA PROCESS AND BATH FOR PIGKLING- METALS No Drawing.

This invention relates to the production ofp ga rficbase from crackedpetroleum one and particularly to the use of sachtas'esi'fi' connection with the pickling of metals. The

invention will be readily understood from the following description.

It is found that petroleum oils which have been subjected to cracking temperatures contain valuable organic bases. For the recovery of these bases it is preferred to employ oils cracked under pressure at temperatures 'ri hichare. usually in .excess of 700 F., an

particularly distillate products therefrom,

such as cracked gasoline and kerosene. It may be" stated specifically 'th'afgoo'd'result-s are obtained with pressure distillate derived from the cracking of mid-continent stock by the Burton process at temperatures of 720760 F. and pressures above 4 atmospheres.

As a specific examplesuch pressure distillate is agitated with about 0.04 lbs. of 50 sulfuric acid per gallon of oil and the acid layer is settled out and withdrawn. The acid solution is then completely wimd with a strong base such as sodium hvdrnxide. whereupon the organic bases separateT- n oily layer on the surface of the solution, and may be removed therefrom by decantation.

If desired, the organic bases may be removed from the neutralized solution by distillation with steam, or by extraction with a suitable solvent such as aht or the like, the organic bases being recovered from the extraction liquid by fractional distillation. The latter methods are particularly suitable where lime is used to neutralize the sulfuric acid, since in that case there is a considerable tendency for the oily bases to become emulsified, rendering separation by decantation difficult and incomplete.

The organic bases may also be recovered from the acid sludges produced by treating such distillates with stronger acid, for example, sulfuric acid of 60 Baum or higher. In this method the acid sludge may suitably be neutralized with alkali and the bases recovered by steam distillation or solvent extraction as indicated above.

drous metals.

Application filed January 18, 1928. Serial No. 247,747.

The bases thus obtained are an oily liquid having a disagreeable odor and comprising a mixture of organic bases of nitrogenous character.

The bases are capable of technical utilization. For example, they have a remarkable efiect in retarding the rate of corrosion of iron and steel and other metals by acid without substantial effect upon the rate of attack on oxides of iron. On this account they may be used in pickling metals, particularly fer- As an indication of this effect it may be stated that two baths of 5 sulfuric acid Were prepared. To one bath 0.135 gram of organic bases obtained as described above was added per liter. Strips of clean sheet iron were immersed in both baths which were maintained at 180 F. Durin a period of 10 minutes the strip immerse in the, pure A dilute acid sufiered a corrosion loss of 27 .5 mg. per square inch, While the strip immersed in similar acid to which the organic bases had been added had a corrosion loss of only 7.2 mg. per square inch.

This effect of the organic bases in reducing the attack of acids upon metals is exhibited by pickling baths of wide ranges of concentration and with wide ranges of added bases. The specific figures given are illustrative only and are intended to set forth a specific pickling bath suitable for commercial utilization.

i lthough the present invention has been described in connection with the details of specific embodiments thereof it is not intended that the specific details shall be regarded as limitations upon the scope of the invention, which is intended to be protected broadly within the scope of the appended claims.

I claim:

1. A pickling bath comprising a dilute acid and organic bases separated from cracked petroleum oil.

2. A pickling bath comprising a dilute acid and a relatively small quantity of separated bases derived from cracked petroleum oil.

3. The method of acid pickling metals which comprises subjecting the metal to the action of an acid pickling bath, and incorpo- 100 rating in said bath separated, free organic bases derived from petroleum.

4. The method of acid pickling metals which comprises subjecting the metal to the action of an acid pickling bath, and incorporating in said bath separated, free organic bases derived from a cracked petroleum oil.

5. The method of acid pickling metals which comprises subjectin the metal to the action of an acid pickling ath, and incorporating in said bath separated, free organic bases derived from a cracked petroleum distillate.

6. A pickling bath comprising a dilute acid and free organic bases derived from petroleum oil.

In testimony whereof I have hereunto set my hand this 4th day of January, 1928.

VANDERVEER VOORHEES. 

